1. Field of the Invention
This invention relates to washers in general and, more particularly, to dishwashers having a straining system for preventing articles from coming in contact with the dishwasher pump.
2. Description of the Related Art
Washers commonly have a tub with a lower region defining a sump. Typically, a pump is mounted at the bottom of the sump and a hub with a spray arm projects upward from the center of the sump. The spray arm is rotatably mounted to the hub and distributes fluid throughout the tub. In such washers, the hub contains a conduit for conducting fluid up to the spray arm. The hub may also contain a portion of the pump such as an impeller. During washing and rinsing operations, the pump recirculates fluid from the sump up to the spray arm. As a result of the operation of the pump and natural forces, solid articles gravitate to the bottom of the sump where the pump inlet is located. If large articles such as knives, forks, pieces of glass, and straws come in contact with the pump, damage may occur to the pump.
It is known to equip washers with strainers to prevent large articles from coming into contact with the pump. Furthermore, it is known to have strainers disposed around a central hub inside the center of the washer. Such strainers shall hereinafter be referred to as annular strainers even though not all such strainers are circular. Known annular strainers extend out radially from the central hub with an upward inclination, with a downward inclination and with no inclination. Examples of such annular strainers include U.S. Pat. No. 4,347,861 to Clearman, U.S. Pat. No. 3,335,867 to Perl and U.S. Pat. No. 3,491,780 to Kaldenberg, all of which are incorporated herein by reference.
In the 867 patent to Perl and the 780 patent to Kaldenberg, the annular strainers are fastened to the central hub by tab and groove means. Other known annular strainers are fastened to the central hub by screws. Annular strainers fastened by screws are secure, but tend to be difficult to remove. Moreover, such strainers require detachable parts. Annular strainers fastened by tab and groove means are easy to remove, but tend to become loose. Accordingly, it would be advantageous to have an annular washer strainer that can be fastened securely without using detachable parts but is easily removable.
Known annular strainers contain openings that are large enough to permit an uninterrupted flow of fluid through the strainer, but are small enough to preclude the passage of large articles. Known annular strainers such as the annular strainer in the 867 patent to Perl contain a substantially uninterrupted pattern of openings. Other known annular strainers contain a plurality of slots that extend out radially. Annular strainers with radial slots permit fluid to flow freely through the strainer and adequately preclude the passage of bulky articles. Annular strainers with radial slots, however, tend to permit the passage of elongated articles such as straws and stirrers that have a small cross-sectional area in relation to their axial length. Accordingly, it would be advantageous to have an annular washer strainer with slots that are not arranged in a radial manner.
The present invention is directed to a straining system having the foregoing desired features.